China has warned against what it ha

China has warned against what it has called “provocative behavior” in the South China Sea.

The warning followed news reports released Thursday. The reports said the United States military is planning to sail warships close to artificial islands China has been building up in the disputed waters.

The reports say U.S. officials have said they are considering sailing warships within about 22 kilometers (or 12 nautical-mile zones) of the artificial islands within the next two weeks. China claims these areas as extensions of its territory.

However, neither the U.S. Defense Department nor the administration of President Barack Obama have confirmed the reports. Last month, U.S. Defense Secretary Ash Carter spoke about the situation in the South China Sea. He said the United States would, “fly, sail, and operate wherever international law allows, as U.S. forces do all over the world.”

The United States does not recognize some of China’s territorial claims in the South China Sea. The Philippines, Vietnam, Taiwan, Malaysia and Brunei all have conflicting claims to several areas and island groups in the sea.

Foreign Ministry spokeswoman Hua Chunying was asked by reporters about possible U.S patrols in the South China Sea on Friday. She said China, in her words, “will never allow any country to violate China’s territorial waters and airspace in the Spratly Islands, in the name of protecting freedom of navigation and overflight.”

The United States has said it will not intervene in the ongoing territorial disputes. But it has said it will protect freedom of navigation in a region that is critical for international shipping.